1. Field of the Invention
The present invention relates to baghouse valves, and more specifically, to unique seal constructions for such valves which are adapted for such uses as by-pass valves, for example.
2. Description of the Prior Art
It has been known for many industrial applications, such as in connection with coal-fired utility boilers, cement kilns and other uses to purify emerging, unclean air and gases through the use of baghouses. In connection with such baghouses, various sorts of flow arrangements and valving concepts for the air or gas being handled have been known. See, for example, U.S. Pat. Nos. 3,898,062; 3,945,400; 3,963,467; 3,975,173 and 4,113,449.
It has also been known to employ poppet-type valves in connection with such usage. For by-pass usage, it is critical that undesired seepage of dirt-containing air or gas through the valve so as to permit undesired comingling with cleaned gas or air be resisted. It has been known to employ double-dished valve elements, each provided with a sealing action at the respective seats and to purge the space between the double-dished heads.
There remains a very real and substantial need for a seal for use in baghouses and, in particular, in respect of by-pass valves for the same, which provide improved efficiency of sealing action, simplicity of design and effective resistance to undesired contamination of cleaned gases or air.